Draft

ADVISORY BOARD ON

RADIATION AND WORKER HEALTH

National Institute for Occupational Safety and Health

SC&A REVIEW OF DCAS-RPT-005, REVISION 00, 

ALTERNATIVE DISSOLUTION MODELS FOR INSOLUBLE 

PLUTONIUM-238 

Contract No. 211-2014-58081 

SCA-TR-2017-PR001, Revision 0 

Prepared by

Joyce Lipsztein, PhD 

SC&A, Inc.

1608 Spring Hill Road, Suite 400 

Vienna, Virginia, 22182 

Saliant, Inc.

5579 Catholic Church Road 

Jefferson, Maryland 21755 

January 2017 

DISCLAIMER

This is a working document provided by the Centers for Disease Control and Prevention (CDC) technical 

support contractor, SC&A for use in discussions with the National Institute for Occupational Safety and 

Health (NIOSH) and the Advisory Board on Radiation and Worker Health (ABRWH), including its 

Working Groups or Subcommittees. Documents produced by SC&A, such as memorandum, white paper, 

draft or working documents are not final NIOSH or ABRWH products or positions, unless specifically 

marked as such. This document prepared by SC&A represents its preliminary evaluation on technical 

issues.

NOTICE: This report has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 U.S.C. § 552a and has been cleared for distribution.
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SC&A, INC.: Technical Support for the Advisory Board on Radiation and Worker 

Health Review of NIOSH Dose Reconstruction Program

DOCUMENT TITLE: 

SC&A Review of DCAS-RPT-005, Revision 00, Alternative 

Dissolution Models for Insoluble Plutonium-238

DOCUMENT NUMBER/

DESCRIPTION:

SCA-TR-2017-PR001 

REVISION NO.: 0 (Draft)

SUPERSEDES: N/A

EFFECTIVE DATE: January 13, 2017

TASK MANAGER: Kathleen Behling [signature on file] 

PROJECT MANAGER: John Stiver, MS, CHP [signature on file] 

DOCUMENT 

REVIEWER(S):

Kathleen Behling [signature on file]

John Stiver, MS, CHP [signatures on file] 

Record of Revisions 

Revision 

Number

Effective 

Date Description of Revision

0 (Draft) 01/13/2017 Initial issue
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TABLE OF CONTENTS

1.0 Introduction ......................................................................................................................... 5

2.0 Review of DCAS-RPT-005, Revision 00 (2016) ............................................................... 5

3.0 Discussion of the Status of the 14 Findings Presented by SC&A in Its Review of 

OTIB-0083, as Addressed in RPT-005. .............................................................................. 7

3.1 Finding 1 ................................................................................................................. 7

3.2 Findings 2, 3, 4, and 5 ............................................................................................. 7

3.3 Finding 6 ................................................................................................................. 7

3.4 Finding 7 ................................................................................................................. 8

3.5 Finding 8 ................................................................................................................. 8

3.6 Finding 9 ................................................................................................................. 8

3.7 Finding 10 ............................................................................................................... 8

3.8 Finding 11 ............................................................................................................... 8

3.9 Finding 12 ............................................................................................................... 9

3.10 Finding 13 ............................................................................................................... 9

3.11 Finding 14 ............................................................................................................... 9

4.0 References ......................................................................................................................... 10
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ABBREVIATIONS AND ACRONYMS

ABRWH Advisory Board on Radiation and Worker Health 

DCAS Division of Compensation Analysis and Support 

ICRP International Commission on Radiological Protection

IMBA Integrated Modules for Bioassay Analysis

LANL Los Alamos National Laboratory 

NIOSH National Institute for Occupational Safety and Health

NUMEC Nuclear Materials & Equipment Corporation

ORAUT Oak Ridge Associated Universities Team

OTIB ORAUT technical information bulletin

Pu plutonium 

SRS Savannah River Site 
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1.0 INTRODUCTION

The National Institute for Occupational Safety and Health (NIOSH) presented DCAS-RPT-005, 

Alternative Dissolution Models for Insoluble Pu-238 (2016, hereafter “RPT-005”) to replace 

ORAUT-OTIB-0083 (hereafter “OTIB-0083”), Revision 0, Dissolution Models for Insoluble 

Plutonium-238 (2013), which was cancelled.

Several changes were made that address most of the 14 findings that SC&A presented in its 

review of OTIB-0083 (SC&A 2013). Those findings were discussed during the February 13, 

2014, Subcommittee on Procedures Review meeting.

2.0 REVIEW OF DCAS-RPT-005, REVISION 00 (2016) 

RPT-005 provides guidance on the evaluation of intakes for workers who were exposed to 

ceramic forms of plutonium-238 (Pu-238). Workers who are exposed to Pu-238 can exhibit 

non-monotonic urinary excretion patterns that are indicative of non-standard lung biokinetics.

RPT-005 indicates that site-specific lung dissolution models should be used in dose 

reconstructions for insoluble forms of Pu-238 as an additional dissolution type, in addition to the 

standard Types M and S. The dissolution type that results in the highest dose to the organ of 

interest should be used for the final dose assignment. 

These additional dissolution types should be used at the Los Alamos National Laboratory 

(LANL), the Mound Site, the Savannah River Site (SRS), and the Nuclear Materials & 

Equipment Corporation (NUMEC). Incidents involving exposure to similar Pu-238 sources at 

other sites should be evaluated on a case-by-case basis, using the LANL model.

As described in RPT-005, the available urinary excretion patterns following intakes of Pu-238 at 

LANL, the Mound Site, and SRS were reviewed. Using these data, parameters for site-specific 

dissolution models were developed for the Mound and LANL sites. 

The report is very well written, with all sections explained in a didactic way. RPT-005 discusses 

the reason for the special lung modeling for exposures to certain ceramic compounds of Pu-238, 

describes the International Commission on Radiological Protection (ICRP) Publication 66 (1994) 

lung dissolution model and its parameters, and provides the applicable inputs into the Integrated 

Modules for Bioassay Analysis (IMBA) software.

The document is scientifically well based. Attachment A, Sections A-1, A-2, and A-3, describe 

the development of personalized model parameters for various individuals who were exposed at 

LANL, Mound, and SRS. Each exposure case is described and the parameters are derived using 

individual bioassay data. Table A-1, Section A-5, provides the lung dissolution parameters 

estimated for workers exposed at LANL, Mound, and SRS. The parameters for standard Type S 

plutonium (S-21) and standard Type M plutonium (M-22) are also given. Figure A-7 shows the 

comparisons of individual curve fittings, using the dissolution parameters from Table A-1. 
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Attachment A, Section A-5, summarizes the lung dissolution parameters that should be used for 

each site. In this section, SC&A has some concerns related to NIOSH’s statement that: 

The parameters for Mound-13 are considered to be representative of those 

observed for Mound cases and should be used as the defaults for Mound and SRS. 

SC&A believes that NIOSH should explain why the parameters for Mound-13 should be used as 

the default for Mound. 

In addition, the inclusion of SRS default parameters in the sentence quoted above, implying that 

the default parameters for Mound should be used for SRS, is probably a typographical error, 

because it contradicts the following paragraph from Section A.5.1: 

The LANL default model is considered to be the most conservative of the models 

and should be used for NUMEC and any other site where a 238Pu dissolution 

model is needed but was not explicitly defined in the report. Given that there is 

only one case available for evaluation at SRS, a site-specific dissolution model 

could not be developed. Examination of Figure A-7 indicates the clearance 

pattern of 238Pu falls somewhere between that of Mound and LANL. Thus, the 

LANL model should also be used for SRS cases. [emphasis added]

SC&A finds the above paragraph to be correct and claimant favorable.

In summary, SC&A has two findings about RPT-005: 

• Finding 1: NIOSH should provide justification for using Mound Case 13 dissolution 

parameters as the default for all Mound workers. 

• Finding 2: The use of Mound Case 13 parameters as a default for SRS workers is an 

apparent mistake. It contradicts the more claimant-favorable statement in the same 

section of the report: “The LANL model should also be used for SRS cases.” 
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3.0 DISCUSSION OF THE STATUS OF THE 14 FINDINGS 

PRESENTED BY SC&A IN ITS REVIEW OF OTIB-0083, AS 

ADDRESSED IN RPT-005. 

Summarized below are the 14 findings identified as a result of SC&A’s review of OTIB-0083 

(SC&A 2013), along with a brief discussion of whether SC&A believes these findings have been 

adequately addressed in RPT-005. 

3.1 FINDING 1

The applicability and target audience of OTIB-0083 is not well defined.

SC&A recommends that this finding be closed: RPT-005 clearly defines the target audiences and 

the U.S. Department of Energy and atomic weapons employer sites that had the potential for 

exposure to this form of plutonium. 

3.2 FINDINGS 2, 3, 4, AND 5

• Finding 2: NIOSH did not demonstrate that Type J plutonium is a material that would be 

rarely encountered in the workplace.

• Finding 3: NIOSH does not explain why Type L was chosen to evaluate the doses for 

certain scenarios, as exemplified in Tables 2-1 and 2-2. Type L was derived based on a 

singular incident that occurred at Mound in 1960. 

• Finding 4: NIOSH did not demonstrate that Type L was commonly found in the 

workplace at Mound or at any other places. 

• Finding 5: NIOSH did not demonstrate that exposures at Mound to Pu-238 that show 

non-monotonic absorption from the lungs may be well characterized by Type L Pu-238, 

at all times and at all areas. 

SC&A recommends that Findings 2, 3, 4, and 5 be closed: These findings can be closed because

RPT-005 refers to the application of lung model “Type L” at Mound, as well as at other sites. 

NIOSH now differentiates the sites (LANL, SRS, NUMEC, and Mound). For Mound, in 

particular, data from various incidents are used to derive the most suitable model for Pu-238 to 

be applied in the installation.

3.3 FINDING 6

NIOSH does not state whether the technical calculations to derive the limiting dissolution types 

should stand as examples of similar calculations to be performed in other facilities besides 

Mound. 

SC&A recommends that Finding 6 be closed: NIOSH now specifies how alternative dissolution 

models for Pu-238 should be applied to different installations. 
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3.4 FINDING 7

NIOSH does not compare organ doses from acute intakes of Type L Pu-238 with chronic intakes 

of Types M and S Pu-238 materials. NIOSH should discuss the limiting dissolution types for 

acute intakes of Type L versus chronic intakes of Type M or Type S Pu-238, as this is an 

important problem in dose reconstruction.

SC&A recommends that Finding 7 be closed: This finding does not apply to RPT-005. 

3.5 FINDING 8

In Section 4, NIOSH defines the parameters for Type L exposures at Mound and compares the 

dissolution curves with Type J and Type S but does not demonstrate that Type L is typical of 

Mound exposures.

SC&A recommends that Finding 8 be closed: This finding does not apply to RPT-005.

3.6 FINDING 9

The purpose of Section 4 is not well defined in relation to other exposures to Pu-238 that show 

non-monotonic behavior at Mound and at other sites.

SC&A recommends that Finding 9 be closed: RPT-005 defines non-monotonic behavior of 

Pu-238 at other sites besides Mound.

3.7 FINDING 10

There is no guidance in either ORAUT-TKBS-0016-5, Revision 02, or OTIB-0083 on which 

areas of Mound and in which time period Tables 2-1 and 2-2 should be used. The lack of such 

guidance implies that the tables should be used at all areas and at all times to interpret Mound 

Pu-238 bioassay results. If this is not NIOSH’s intent, then either ORAUT-TKBS-0016-5, 

Revision 02, or OTIB-0083 should be modified to specify where and when Tables 2-1 and 2-2 

should be used. 

SC&A recommends that Finding 10 be closed: Alternative models for dissolution of Pu-238 are 

defined in Attachment A, Section A-5.1.

3.8 FINDING 11

For sites other than Mound where non-monotonic behavior of Pu-238 is observed, there is no 

assurance that the Pu-238 behavior at that site will correspond to Mound’s Type L Pu-238 

behavior. There is no information in OTIB-0083 on how to deal with exposures to Pu-238 

material that present dissolution parameters different from Types M, S, and L. Thus, the 

usefulness of OTIB-0083 to sites other than Mound is questionable.

SC&A recommends Finding 11 be closed: Alternative models for dissolution of Pu-238 are 

defined for different sites and summarized in Attachment A.
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3.9 FINDING 12

OTIB-0083 is difficult to follow and understand. The sections do not follow a natural order. 

NIOSH’s Type J and NIOSH’s Type L Pu-238 compounds are only introduced in Section 4, 

although they are used in Sections 1, 2, and 3. 

SC&A recommends that Finding 12 be closed: This finding does not apply to RPT-005. 

3.10 FINDING 13

OTIB-0083 is essentially the same document as the white paper, Modeling Intakes of Pu-238 at 

Mound (LaBone and Brackett 2009). OTIB-0083 is only clear for those that participated in 

discussions regarding Pu-238 exposures at Mound. 

SC&A recommends that Finding 13 be closed: This finding does not apply to RPT-005. 

3.11 FINDING 14

OTIB-0083 does not discuss the existence of other non-monotonic forms of Pu-238 at Mound, 

nor present any research done to prove that Type L is the only appropriate form of Pu-238 to be 

included in the calculation of the limiting dissolution type.

SC&A recommends that Finding 14 be closed: For Mound, data from various incidents are used 

to derive the most suitable model for Pu-238 to be applied in the installation. 
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4.0 REFERENCES

DCAS-RPT-005, 2016. Alternative Dissolution Models for Insoluble Pu-238, Revision 00,

National Institute for Occupational Safety and Health, Division of Compensation Analysis, 

Cincinnati, Ohio. June 28, 2016.

ICRP 1994. Human Respiratory Tract Model for Radiological Protection, International 

Commission on Radiological Protection, ICRP Publication 66, Ann. ICRP 24 (1-3), 1994. 

[SRDB Ref. ID 22732]

LaBone and Brackett 2009. T. LaBone and E. Brackett, Modeling Intakes of Pu-238 at Mound,

National Institute for Occupational Safety and Health, Cincinnati, Ohio. January 30, 2009.

ORAUT-OTIB-0083. 2013. Dissolution Models for Insoluble Plutonium-238, Revision 00, Oak 

Ridge Associated Universities Team, Cincinnati, Ohio. April 12, 2013.

ORAUT-TKBS-0015-5. 2013. Technical Basis Document for the Mound Site – Occupational 

Internal Dose, Revision 02, Oak Ridge Associated Universities Team, Cincinnati, Ohio.

April 18, 2013.

SC&A 2013. Review of ORAUT-OTIB-0083, Rev. 00, Dissolution Models for Insoluble 

Plutonium-238, SCA-TR-PR2013-0087, Revision 0, SC&A, Inc., Vienna, Virginia. 

December 24, 2013.